Regulation of gene expression by transcription factors is one of the most fundamental biological processes. The pharmaceutical manipulation of this process would open doors toward new approaches to treatment of cancer and other major diseases. We aim to develop a novel, comprehensive technology for manipulation of gene expression based on synthetic analogues of eukaryotic transcription factors. The design and synthesis of these artificial transcription factors (ATFs) has been accomplished in Phase I by replacing functional domains of natural transcription factors with artificial chemical moieties. These ATFs have a remarkably high biological activity combined with novel properties resulting from their unique chemical composition and structure. In Phase II we propose to develop ATF technology further and apply it to target selected human genes in their native, chromosomal setting in tissue culture cells. This will be achieved by using a combination of chemical, biochemical, genetic and genomic tools. The specific aims of this proposal are: 1) Expanding the repertoire of ATFs with new chemical moieties. 2) Developing a robust and rapid assay for testing of ATFs in human cell culture lines. 3) Demonstration of the ability of ATFs to target selected endogenous human genes in tissue culture.